In 1965, the Race Relations Act banned all discrimination in the workplace.

Peaceful protests were organised across Bristol

The boycott came about after Guy Bailey, a Jamaican new to the UK, was openly refused a job by a manager at the bus company because "we don't employ black people".

A group, led by Dr Stephenson, and inspired by the equality campaigns of Martin Luther King in North America's south and the actions of Rosa Parks, who refused to give up her seat to a white passenger on a Montgomery bus, urged a boycott of the service until the policy of discrimination was ended.

Starting in April 1963, pickets of bus depots and routes were part of the strategy, with blockades and sit-down protests organised on routes throughout the city centre.

On 28 August 1963, the same day that Martin Luther King delivered his momentous 'I have a dream' speech in Washington DC, the Bristol Omnibus Company declared a change in policy that there would now be "complete integration" on the buses "without regard to race, colour or creed".

By September, the company had its first non-white bus conductor.

Guy Bailey OBE, Roy Hackett and Dr Paul Stephenson OBE took part in the campaign in the 1960s

Dr Stephenson said the boycott has become "a watershed" on how the city comes to terms with its ethnic minority make-up.

"As Martin Luther King once said: 'We face chaos or community; the choice is ours'," said Dr Stephenson.

Bristol's mayor, George Ferguson, who attended the ceremony in the bus station said the campaigners are "etched into Bristol's history and should be celebrated as heroes of our time".